What Is Loeffler’s Syndrome?

Introduction

Loeffler's syndrome is an eosinophilic pulmonary disease with less or absent respiratory symptoms. The condition was described by Wilhelm Loffler in 1932. The other terms for the syndrome are nematode pneumonitis, Ascaris pneumonia, and eosinophilic pneumonia. The article provides detailed insights into Loeffler’s syndrome.

What Is Loeffler Syndrome?

Loeffler’s syndrome is a condition where significant eosinophils collect in the lungs due to parasitic infections. Ascaris lumbricoides are the main culprit for causing parasitic infections that lead to Loeffler’s syndrome. Loffler’s syndrome is a rare and self-limiting condition, and the disease lasts for a short period. The characteristic features of the syndrome are the development of pulmonary infiltrates, elevated eosinophil levels in the blood, and clinical symptoms of wheezing and dyspnea (shortness of breath).

Loffler’s syndrome is of two types:

1. Loffler Syndrome I: It is an eosinophilic volatile infiltrate.

2. Loffler Syndrome II: Exhibits restrictive cardiomyopathy.

What Is Loffler Syndrome II?

The condition is also known as Loffler’s endocarditis. In this condition, the relaxation of heart muscles is defective, leading to impaired diastolic filling. Diffuse eosinophil infiltrates in the heart were noticed by Wilhelm Loffler in 1936. The symptoms include arrhythmia, intracardiac thrombus formation, or heart failure. The syndrome can be life-threatening if not treated early.

What Is the Incidence of Loffler Syndrome?

The syndrome is more common in tropical and temperate countries. It affects men and women equally and is frequent in 16 to 40 years old. Cardiac involvement is present among 50 percent of patients.

What Are the Causes of Loeffler Syndrome?

The development of Loeffler’s syndrome could be due to various causes:

• Allergic response to transpulmonary migration of helminth larvae such as Ascaris lumbricoides, Strongyloides, and hookworm.

• Neoplasms such as myeloproliferative or stem cell disorders like leukemia and lymphoma could lead to Loeffler’s syndrome II.

• Inhalational allergens, such as plant pollen, fungal spores, or industrial agents.

• Hypersensitivity reaction to drugs like Sulfonamides, Penicillin, and gold compounds. Symptoms may develop immediately after taking medication or several days after treatment.

• One-third of patients did not have an identifiable etiologic agent. Idiopathic eosinophilic syndrome (a fatal condition caused by elevated eosinophil levels involving multi-organ complications) is a common cause of Loffler’s endocarditis.

These causative factors increase eosinophil levels in the blood that travel to the lungs and secrete cytokines that induce lung damage.

What Are the Main Symptoms of Loeffler Syndrome?

Symptoms of Loeffler’s syndrome develop 10 to 15 days following infection. Most individuals with Loeffler’s syndrome I are asymptomatic, but some do develop symptoms like:

• Productive or dry cough.

• Shortness of breath can worsen gradually due to eosinophil deposition, leading to organ damage.

• Coughing blood.

• Wheezing.

• Mild fever.

• Muscle pain.

• Weight loss.

Symptoms of Loeffler’s Syndrome II

• Acute heart failure.

• Dyspnea.

• Palpitations.

• Chest pain.

• Cough.

• Fatigue.

• Shortness of breath.

• Unintended weight loss.

The symptoms disappear one to two weeks following the initiation of treatment.

What Is the Mechanism Through Which Loeffler Syndrome Develops?

The exact mechanism through which the infection could damage organs is unknown. Few theories suggest that elevated eosinophil levels for more than five months could cause heart, lung, spleen, central nervous system, and gastrointestinal tract damage.

• Infectious agents or parasites enter the human host by inhalation, orally, or penetrating the skin. The pathogens reach the lungs via blood vessels.

• They invade the alveoli and mature. The infection spreads within the airway, and it further spreads to the small bowel through the alimentary tract.

• Inflammatory Response - When eosinophils enter the heart, they generate protein granules that lead to heart damage due to direct toxin release and platelet activation.

• The platelets coalesce to form thrombi that further damage the heart.

How Is Loeffler Syndrome Diagnosed?

Loeffler’s syndrome diagnosis is by clinical examination or radiographic imaging.

• Imaging - Chest X-rays or CT (computed tomography) scans enable visualization of pulmonary infiltrates.

• Blood Tests - Additionally, a complete blood count and IgE (immunoglobulin E) level assessment may be prescribed. The normal eosinophil count is between 1 to 5 percent, but patients with Loeffler’s syndrome have 500 eosinophils/mm3 (millimeter cube), which comes to around 25 to 30 percent of the total leukocyte count in the body.

• Other Body Fluid Analysis - Other tests include assessment of sputum, gastric, or bronchoalveolar lavage. In drug-induced Loeffler’s syndrome, the eosinophils form 40 percent of the total leukocyte count.

• Stool Examination - In the case of parasitic infection, the eggs in feces appear eight weeks following infection. The parasites need eight weeks to develop into larvae and release eggs. Numerous parasite eggs are released through feces. The pulmonary symptoms clear when the parasites tend to appear in feces.

• Imaging Methods - Loeffler’s syndrome II is diagnosed with an electrocardiogram, echocardiogram, or cardiac magnetic resonance imaging. However, endomyocardial biopsy is a gold standard diagnostic modality.

How Is Loeffler Syndrome Treated?

Loeffler’s syndrome is treated based on the underlying cause. For both types, similar therapeutic interventions are followed. Additional supportive care is given to type II syndrome due to cardiac involvement.

• Anti-parasite Medications - If parasites are the cause of the syndrome, anti-parasite medications are taken. They inhibit parasite growth and prevent late complications like diarrhea, malnutrition, and intestinal obstruction from developing. The most frequently used anti-parasite drugs are Albendazole, Praziquantel, or Ivermectin.

• Corticosteroids - If the syndrome is caused by medication, the drug must be stopped. In severe cases of parasitic or drug-induced Loffler's syndrome, administering corticosteroids can be effective. Early administration of corticosteroids must be avoided, as they can pose diagnostic difficulties. Prednisolone is the preferred corticosteroid administered at a dose of 15 to 20 milligrams per day, followed by a dose reduction of 5 milligrams every other day. The steroid treatment is for six to eight days.

• Adrenomimetics - If bronchial obstruction syndrome is present, adrenomimetics are given as inhalation and Aminophylline orally. Basic treatment for bronchial asthma is provided. However, most patients with Loffler’s syndrome find their symptoms resolving within a month without needing treatment.

• Supportive Care - Loeffler’s syndrome type II requires symptomatic management with supportive care such as diuretics and Digoxin, along with conventional treatment with aldosterone-converting enzyme inhibitors, angiotensin II receptor blockers, and aldosterone antagonists. Additionally, maintaining good hygiene is essential to prevent parasite infection. It is important to keep the nails trimmed, wash food before cooking, and wash hands frequently to avoid infections.

What Are the Anesthetic Considerations for Loeffler Syndrome?

When anesthesia is given in Loeffler’s syndrome I, the adult larvae migrate erratically into the upper airway. It can lead to life-threatening complications like airway obstruction before or after extubation. The pathogen might migrate into the endotracheal tube, leading to respiratory arrest. Among all the parasites, Ascaris is more sensitive to anesthetics and causes the worm to be hypermobile.

Conclusion

Loeffler’s syndrome is a rare entity, and it is difficult to diagnose the disease. Radiographic imaging, respiratory symptoms, peripheral blood eosinophilia, and histopathological findings can aid in diagnosis. Adequate diagnosis is essential for treatment. However, more patients have their symptoms resolved without needing treatment.